Water heaters tend to buildup lime or other sediment in the bottom of the storage vessel over time, which sediment increases the thermal insulation of the vessel and lowers the heat transfer through the bottom of the vessel into the stored water. This sediment build up can cause an increase in the temperature of the lining of the storage vessel during heating operation as the result of the thermal insulating effect. In addition, the efficiency of the water heater is decreased, because more fuel is required to heat the stored water as a result of the insulating sediment.